Electrically operated type wheel setting means



July 5, 1966 Original Filed Dec. 20, 1961 B. a. SCHIERBEEK Re- 26,057

ELECTRICALLY OPERATED TYPE WHEEL SETTING MEANS 5 Sheets-Sheet 1 II/IIIINVENTOR: BEREND B. SCHIERBEEK July 5, 1966 B. a. SCHIERBEEK Re. 26,057

ELECTRICALLY OPERATED TYPE WHEEL SETTING MEANS Original Filed Dec. 20,1961 5 Sheets-Sheet 2 INVENTOR;

BEREND B, SCH IERBEEK ATT'YS July 5, 1966 B. B. SCHIERBEEK 25,057

ELECTRICALLY OPERATED TYPE WHEEL SETTING MEANS 5 Sheets-Sheet 5 OriginalFiled Dec. 20, 1961 INVENTOR: BEREND B. SCHlERBEEK United States Patent26 057 ELECTRICALLY OlERATED TYPE WHEEL SETTING MEANS Berend B.Schierheek, Leidschendam, Netherlands, assignor to Maatschappij vanBerkels Patent N.V., Rotterdam, Ictherlands, a limited-liability companyof the Netherlands Original No. 3,179,044, dated Apr. 20, 1965, Ser. No.160,838, Dec. 20, 1961. Application for reissue Nov. 26, 1965, Ser. No.515,802

8 Claims. (Cl. 101-93) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates in general to a printing device, and moreparticularly to a printing device that responds to electrical controland is capable of printing numerical values, and more particularly to aprinting device for printing numerical measured values wherein thedevice may be set, caused to print and reset for a subsequent printingoperation in a short period of time.

Moreover, the device of the present invention may be employed as anindicator device, wherein indicator wheels are substituted for printingwheels and aligmnent of symbols 0 several wheels in a row will indicatea value.

The rinting device of the present invention particularly suitable forprinting of scale weights of goods and/ or measured values of the goodswith or without unit prices and together with other information on acard or a paper tape. The device may be set for printing either manuallyor automatically and Where automatically by electronic computers,digital measuring instruments, mechanical accounting machines or anyother suitable mechanism.

Accordingly, it is an object of this invention to proivde a new andimproved printing device capable of printing measured, computed orotherwise set values in a short period of time.

Another object of this invention resides in the provision of a printingdevice that is economical to build and simple in construction therebyreducing maintenance problems.

A still further object of this invention is to provide a printing devicethat may be quickly set in response to electromechanical apparatus for aprinting operation.

Other objects, features and advantages of the invention will be apparentfrom the following detailed disclosure, taken in conjunction with theaccompanying sheets of drawings, wherein like reference numerals referto like parts, in which:

FIG. 1 is an elevational view, with some parts in section and otherparts broken away for purposes of clarity of a printing device accordingto the invention;

FIG. 1A is a fragmentary transverse sectional view taken substantiallyalong line 1A1A of FIG. 1;

FIG. 2 is a transverse sectional view taken substantially along line 22of FIG. 1;

FIG. 3 is a schematic view of the contact plate employed with theprinting device of FIG. 1;

FIG. 4 is a transverse sectional view taken through a modified printingdevice according to the invention;

FIG. 5 is an exploded view of a modification of the invention as to thestructure of the printing wheels;

FIG. 6 is an enlarged detail sectional view taken substantially alongline 6-6 of FIGS. 5 and FIG. 7 is an enlarged transverse sectional viewtaken substantially along line 77 of FIG. 10;

FIG. 8 is an enlarged sectional view taken through one of the frictionshoes used for frictionally coupling a printing wheel to the main powershaft;

Re. 26,057 Reissuecl July 5, 1966 "ice FIG. 9 is a somewhat explodedview, illustrating the relationship of a friction shoe with respect to agroove on the shaft and how the spring applies pressure against theshoe;

FIG. 10 is an enlarged, broken and fragmentary view of a portion of apair of printing wheels and illustrating where the shoes are received bythe wheels;

FIG. 11 is an enlarged fragmentary and partially sectional view of aprinting wheel associated with the main shaft and showing how a shoe isheld in place by a spring in engagement with the shaft;

FIG. 12 is a side elevational view of a printing wheel of thisembodiment showing the notched side thereof;

FIG. 13 is a fragmentary sectional view with some parts broken away andtaken axially of the main shaft and showing a pair of printing wheels inassociation with each other;

FIG. 14 is a transverse sectional view taken along line 1414 of FIG. 13and illustrating some parts schematically;

FIG. 15 is a sectional view taken through the printing wheel stop barand illustrating a modified switch for use in detecting themalfunctioning of a printing wheel; and

FIG. 16 is a schematic electrical diagram of circuitry for use with theprinting wheel arrangement and illustrating the manner in which theprinting wheels may be set in response to a pattern of signals.

Referring now to the drawings, and particularly to FIGS. 1 and 2, aprinting device, according to the invention, generally designated by thenumeral 10, includes a plurality of printing wheels 11, l2. 13, 14 and15 mounted for free rotation of an elongated shaft 16. The shaft 16 isrotatably carried by hearing members 17 and 18 mounted on a frame 19 andis continuously driven in the direction indicated by the arrow 20, FIG.2, by any suitable means.

A spring or wave washer 21 is positioned between the adjacent printingwheels and on the outside ends of the printing wheels 11 and 15. Eachwasher includes a lock detent 22 which engages in a longitudinal slotformed in the shaft 16 so that the washers co-rotate therewith. Thewashers are compressed to exert friction pressure against the printingwheels which are urged against a fixed bushing 23 by means of theadjustable collar 24. Thus, a friction clutching relationship existsbetween the shaft 16 and the printing wheels so that the printing wheelsturn with the shaft unless they are restrained by some means.

As may be seen particularly in FIG. 1, each printing wheel is providedwith a plurality of symbols such as numerals. An inked ribbon 25 isarranged below the printing wheels and over a printing tape or card 26.When a printing action is desired, a hammer 27 forces the tape 26against the inking ribbon and against the symbols on the printing wheelsso that the upper side of the tape 26 is elfcctively printed.

The printing wheels 11, 12, 13, 14, and 15 have integrally connectedthereto ratchet portions 28, 29, 30, 31 and 32, respectively. Eachratchet portion includes a plurality of teeth 33 and a single enlargedtooth 34 which coact with electrically operable pawls 35 for stoppingthe wheels. Each pawl 35 is pivotal on a pin 36 and has integrallyconnected thereto a pawl actuating arm or plate 37 that is aligned withand responds to the energization and deenergization of an electromagnet38. When the electromagnet or coil 38 is energized, the pawl actuatingarm 37 will be drawn thereagainst and thereby swing the pawl. 35 intothe path of the ratchet portion to engage a tooth and stop movement ofthe wheel. Each printing wheel coacts with an electromagnet operatedpawl assembly, and where the assembly might take up more space than thewidth of a printing wheel, the pawls and electromagnets may be staggeredsuch as shown in FIG. 2 wherein the pawl a pivotal on a pin 36a andhaving a pawl arm 37a coacting with an electromagnet 38a would serve tocoact with the ratchet portion 28 of the printing wheel 11. It shouldalso be appreciated that a solenoid may be employed in place of anelectromagnet, wherein the plungers thereof would be suitably connectedto the pawl arms. While five printing wheels are shown on the shaft 16,it should be appreciated that a greater or lesser number may be employeddepending on the particular needs of an installation.

In order to synchronize the positions of all printing wheels prior tothe setting thereof at a numerical value, a stop or synchronizing pawl41 carried on a pawl arm 42 pivotal on a pin 43 is provided forselective engagement only with the enlarged ratchet tooth on each of theratchet portions, such as the tooth 34 on the ratchet portion 29, FIG.2. The pawl 41 stops the printing wheel at a predetermined synchronizedlocation. The tooth 34 extends radially outwardly from the teeth 33which are engaged by the pawl 35. And the stop pawl 41 is arranged sothat it will not engage the teeth 33. A similar pawl is provided foreach of the ratchet portions to act as a stop in engaging the enlargedtooth. A single electromagnet 44 serves to deactivate the pawl 41 orraise it to a position out of the path of the enlarged teeth or thetooth 34 so that the printing wheels can then rotate with the shaft.With all of the printing wheels in the same position as defined by thepawl 41, they will all register the same numerals and when they arereleased, the various electromagnet operated pawl and ratchet assembliesmay be subsequently sequentially operated to set a predetermined valuein the printing device.

A modified stop or synchronizing arrangement is shown in FIG. 4, whereinthe ratchet portion 29a is provided with a stop or recessed portion 45for coaction with a stop pawl 46 that is normally arranged to engage theratchet portion. The stop pawl 46 is pivotally mounted on a shaft 47.However, in this instance, the main shaft 16 will oscillate whenresetting the printing wheels to their home position defined by the stoppawl 46.

Referring again to FIG. 1, a contact plate 48 made of insulatingmaterial is mounted on the frame 19 and provided with an one sidethereof a continuous electrical conductor ring 49 and a plurality ofconductor contacts 50 of a number equal to the number of symbols on theprinting wheel. A wiper arm or contact arm 51 is mounted on aninsulating ring 52 carried on the shaft 16 for engagement with theconductor ring 49. A second wiper arm or contact arm 53 is also carriedby the insulating ring 52 and is adapted to engage the circumferentiallyspaced and concentrically arranged conductor contacts 50. The contactarms 51 and 53 are electrically connected, and as shown in FIG. 3, aconductor is connected to each of the conductor contacts 50 representinga numeral. The contact arm 53 is synchronized with the printing wheelsbefore each setting of the Wheels, and therefore also frictionallycoupled to the shaft 16 and provided with an enlarged tooth 52a, FIG.1A, for engagement by the stop pawl carried by the arm 42.

Referring now particularly to FIG. 16, a schematical electric diagramshown therein illustrates the operation of the printing device in thesetting of the printing wheels wherein a line 54 effectively connectsthe wiper arm 53 through the ring conductor 49 to an actuating switch55. An electrical power source 56 is connected in series with the switchand in turn with one side of electromagnets 38a and 38 which areassociated respectively with the printing wheels 11 and 12. A thirdelectromagnet 38b is shown which may be associated with the printingwheel 13 in the same capacity as electromagnets 38a and 38 areassociated with printing wheels 11 and 12. Other electromagnets wouldalso be provided which would be associated with the printing wheels 14and 15, but are not shown herein for purposes of simplicity. Theelectromagnets 38a, 38 and 38b are in turn respectively connected to oneside of each of a series of switch contacts 58, 59 and 60, respectively,in a control panel or relay outlet of a digital measuring instrumentsuch as illustrated in general by the numeral 61. Each of the series ofswitch contacts 58, 59 and 60 are provided with ten switches, one foreach of the numerals as illustrated in the column generally designatedby the numeral 62. The switch contacts in each of the series of eachdigit are connected in series between the electromagnets and theconductor contacts 50 on the contact plate 48.

Holding circuits are provided for each of the electromagnets 38a 38 and38b which respectively include switch contacts 39a, 39 and 39b thatclose upon energization of the respective electromagnets to override thewiper 53 and contacts 50 and hold the electromagnets in energizedposition after they have been momentarily energized by the wiper arm 53passing over the appropriate conductor contacts 50. However, where thepawls on the ratchet are self-locking, the holding circuits and theassociated switch contacts may be omitted since momentary energizationof an electromagnet will cause a corresponding pawl to be swung againstthe ratchet portion and lock against a tooth.

In illustrating the operation of the printing device, where the numerals8, 3, 5 are desired to be printed respectively on the printing wheels11, 12 and 13, the respective switch contacts in the series 58, 59 and60 will be closed. Thereafter, when the actuating switch 55 is closed,the stop pawl 41 is lifted out of engagement from the enlarged pawls onthe ratchet portions such as the pawl 34 by action of the electromagnet44 thereby releasing the printing wheels and the insulating ring 52 forrotation together by the frictional coupling with the shaft 16 that iscontinually rotating in one direction. When the wiper arm 53 engages theconductor contact 50 corresponding to the digit 8, the circuit for theelectromagnet 38a is closed to swing the associated pawl 35a against theratchet portion of the associated printing wheel 11 to thereby engagethe tooth 33 corresponding to the digit 8 and stop the printing wheel sothat the numeral 8 is in printing position, and at the same time toclose the switch contact 39a in the associated holding circuit tomaintain the electromagnet in energized position after contact betweenthe wiper arm 53 and the conductor contact 50 corresponding to the digit8. Thereafter, the contact arm 53 will pass over the conductor contact50 which corresponds to the numeral 5 to thereby energize theelectromagnet 38b to stop the printing wheel 13 and close the associatedholding circuit controlled by switch contact 39b. Finally, the wiper armwill pass over the conductor contact corresponding to the numeral 3 tothereby energize the electromagnet 38 and stop the printing wheel 12.And again the holding circuit for the electromagnet 33 will besimultaneously energized by closing switch contact 39. With the holdingcircuits energized, the printing wheels will remain in their setposition. All of the printing wheels continue to rotate by means oftheir friction drives until they are stopped. And after a fullrevolution has been established, all of the printing wheels are in theirdesired printing positions so that the hammer 27 can be actuated toprint the set numbers against the paper tape 26. Thereafter theactuating switch 55 may be opened to release the printing wheels andresume the frictional coupling between the wheels and the shaft so thatthe wheels and insulating ring 52 with the wiper arm may be driven backto home position until the enlarged teeth abut against the stop pawl 41.The printing device is then ready for the next printing operation to beagain initiated by selecting the digits by closure of switch contacts inthe series 58, 59 and 60 and by energization of electromagnet 44 torelease the wheels and insulating ring.

The embodiment of FIG. 4 operates in the same way including the printingoperation, except that the shaft 16 revolves in the opposite directionafter the printing operation has been completed to drive the printingwheels to their home positions as defined by the stop pawl 46 and thestop 45.

The preferred embodiment of the invention as to the construction of theprinting wheels, their mounting on the drive shaft, and the pawl andratchet mechanism is shown in FIGS. 5-14, wherein printing wheels 63 arefricti-onally coupled to a drive shaft 64 that is oscillatably driventhrough 120 revolutions by any suitable means. Each printing wheelincludes a printing section 65 having a plurality of printing segments66, a ratchet section 67 having a plurality of ratchet teeth 63, and arecessed section 69. Radial stops 70 and 71 on each printing wheel aredefined by the recessed section 69 and are respectively at one end ofthe ratchet section and one end of the printing section, and coaot witha stop bar 72 for operation of each printing wheel. Each of the sections65, 67 and 69 span approximately one-third of the circumference of eachprinting wheel or an arcuate area of 120.

The shaft 64 is provided with a plurality of axially spaced,circumferentially extending, annular wedge-shaped grooves 73 which coactwith brake or friction shoes 74 received in radial slots or guides 75 ineach of the printing wheels to frietionally couple the printing wheelsto the shaft whereby each wheel will rotate with the shaft unlessrestrained by a force sufficient to overcome the friction coupling. Theshoes also prevent the wheels from moving axially along the shaft. Apair of the brake shoes are provided for each printing wheel and areresiliently biased against the shaft and into the wedge-shaped groove 73by means of a curvilinear spring 76 that is provided with a detent 77 ateach end thereof engageable in a socket or recess 78 formed in the outerend of a brake shoe 74. Thus, each printing wheel is frictionally(oupled to the shaft by means of the brake shoes 74 engaging in thewedge-shaped grooves 73. And the printing wheels will rotate oroscillate with the shaft unless they are held stationary relativethereto. A solenoid or electrom-agnet operated, self-locking, pawl 79 isprovided to enact with the ratchet teeth 68 on the ratchet section 67 ofa printing wheel. Each of the printing wheels is provided with a pawlwhich, as illustrated, is pivotal about a pin 80 and actuated intoengagement with the teeth 68 by means of a solenoid 81 through linkage82, FIG. 14. An electromagnet arrangement similar to that employed inthe embodiment of FIGS. 1 and 2 may be used in place of the solenoidarrangement. Thus, when the shaft 64 is rotated in a clockwise directionduring its oscillation, it will carry the printing wheels therewithunless the solenoid 81 for any respective printing wheel is energized toactivate the pawl 79 into engagement with one of the ratchet teeth 68.after which the respective printing wheel will be held from furtherrotation with the shaft. All those printing wheels associated withsolenoids that are not stopped by respective pawls will continue torotate with the shaft 64.

Any number of printing wheels 63 may be mounted along the shaft ingroups or in complete side-by-side relationship depending on the needsof a particular installation. The printing wheels, when placed inside-iby-side relation such as in FIGS. 6 and 7 are arranged in somewhatnested relation. An annular notch 83 is formed on one side of each wheelonly along the printing and ratchet sections that may freely receive apart of an adjacent wheel. An axial extending portion 48 opposite thenotched side of the wheel includes an annular slot 35. Along theprinting and ratchet sections, the slot is deepened by an extension lip86 to receive the spring 76 and maintain its against lateral movement asmay be seen in FIGS. 6 and 7.

The shoe receiving slots 75 which extend generally radially through theextending pontion 84 coaot with the extension lip 86 in maintaining theshoes against circumferential and axial movement. And the lip 86 isopened along the center portion of each shoe for facilitating insertionand removal of the shoes although it may be closed if so desired.

Each shoe is made of a bearing like material since it must be capable ofhaving sliding contact with the shaft. Moreover, each shoe has anarcuate shaft engaging edge, which in cross section preferably includesa pair of beveled surfaces 88 and 89 extending between the sides of theshoe and a horizontal surface 90, whereby the beveled surfaces 88 and 89engage the beveled surfaces of a shaft groove 73. And the horizontalsurface 90 gives a blunt edge which will not engage the base of a groove73.

Inasmuch as the pawls 79 associated with the ratchet teeth 68 aremechanically self-locking, it is only necessary to momentarily energizethe solenoids 81 in order to lock the printing wheel in position.Accordingly, the holding circuits, as shown in the schematic diagram ofFIG. 16 would not be used. Additionally, an insulating ring will also beoscillatable with the shaft 64 in synchronism with the printing wheelsfor operating the wiper arm 53 across the conductor contacts 50. But inthis case, the insulating ring maybe secured to the shaft at all timesalthough it will be arranged so that the wiper arm need only passthrough a 120 revolution in order to cover all of the contacts 50 in amanner shown in FIG. 16.

After the printing device of FiGS. 514 has completed a printing cycle,the shaft is then oscillated in the counter-clockwise direction, and theprinting wheels are returned to the home position to reset the wheelsfor another printing cycle wherein the radial stops 70 of each wheelengage the stop bar 72.

In this embodiment, there may be provided eleven printing segments 66,one for each of the ten digits, and one for a symbol such as a star orasterisk, whereby upon the malfunctioning of any solenoid and paw]arrangement, the particular printing wheel involved will be driven tothe position where the radial stop 71 engages the stop bar 72 and atthat point the printing segment having the star or asterisk will be inprinting position to indicate to the operator that the printing deviceis malfunctioning. This feature could also be incorporated in theembodiment of FIGS. 1 and 2 by adding another printing segrnent. i

There are also ten teeth 68 on each wheel corresponding to the tendigits. For example if tooth 68a, FIG. 13, is engaged by the pawl 79,the numeral 0 on segment 66a would be in printing position, whileengagement of the tooth 681) would place the numeral "9" on segment 66bin printing position. And if the solenoid failed to operate, theprinting wheel stop 71 would engage the stop bar 72 and bring theasterisk on segment 66c into printing position.

Additionally, the stop bar 72 may have associated therewith a sensing ordetecting mechanism for detecting whether or not at least one of theprinting wheels has completely rotated thereagainst to the positionwhere the asterisk or other symbol would be printed and only in suchcase where a solenoid has malfunctioned. In this instance, a sensingswitch 91 would be positioned to be closed by the stop 71 if it travelsto the stop bar 72. Closing of the sensing switch 91 will energize acircuit having a power source 92 and an alarm or signal 93 therein tofurther indicate to the operator that the printing device ismalfunctioning. The alarm or signal 93 may take the form of a buzzer,bell, light, or other suitable means.

An alternate sensing switch is shown in FIG. 15 wherein an insulator 94is secured to the stop bar 72 and has secured thereto an electricalcontact 95. The contact 95 would be fixed and the radial stop 71 wouldfunction as a movable contact, both contacts functioning to replace theswitch 91. Thus, one side of the alarm circuit would be electricallyconnected to the printing wheel and the other side to the contact 95.

This feature of having a signal to indicate malfunctioning could also beincorporated in the embodiment of FIG.

2 wherein a sensing switch would be associated with the stop pawl 41 butwould be alive and operate only during the printing part of the cycleinasmuch as this stop is also used to synchronize the printing wheelswhen they are brought to their home position.

Although the printing wheels disclosed are provided with numbercharacters, it should be appreciated that any number of alphabeticalcharacters may be provided on a printing wheel with a like number ofratchet teeth so that any character may be brought into printingposition. If all of the letters of the alphabet were arranged on awheel, then a similar number of selection switches and wiper armcontacts would be provided. Moreover, means for selectively stopping thewheels other than a pawl and ratchet arrangement may be employed.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention, but it is understood that this application is to be limitedonly by the scope of the appended claims.

I claim:

1. A printing device for printing a series of selected characters duringthe printing phase along a line comprising, a rotatable shaft, means forcontinuously rotating said shaft in one direction, a plurality ofprinting wheels mounted on said shaft and frictionally coupled theretoto normally rotate therewith, first means for stopping said wheels topreset same at a home position and thereafter releasing same, eachprinting wheel having a character section and a ratchet section, aplurality of characters equally spaced along the character section, aplurality of ratchet teeth equally spaced along the ratchet section, andsecond means coacting with said ratchet section for stopping said wheelssubsequent to their release by said first means including, a pawlaligned with each ratchet section and adapted to engage one of the teeththereon and stop each printing wheel from rotating with the shaft, anelectrically operated actuator for each pawl for driving same into andout of engagement with its respective ratchet section, settablc controlmeans defining selected character positions of each wheel, and switchmeans associated with each actuator and operated by said shaft insynchronism with said printing wheels for selectively energizing eachactuator to move each pawl into engagement with a tooth on a ratchetsection and stop each printing wheel at a preselected position asdetermined said settablc control means for printing as series ofpreselected characters, said switch means including a single wiper armfrictionally coupled on said shaft and synchronized at home positionwith said wheels by said first means, and spaced contacts engageablewith said wiper arm when operated by said shaft.

2. A printing device as defined by claim 1, and means coacting with saidwheels for detecting the non-operation of each actuator during theprinting phase.

3. A printing device as defined by claim 2, wherein said detection meansincludes a signal circuit energized by the non-operation of an actuatorduring the printing phase.

4. A printing device for printing a series of selected characters duringthe printing phase along a line comprising, a shaft, means foroscillating said shaft through a partial revolution, a plurality ofprinting wheels mounted on said shaft and frictionally coupled theretoto normally oscillate therewith, first means for stopping said wheels topreset same at a home position and thereafter releasing same, eachprinting wheel having a character section and a ratchet section, aplurality of characters equally spaced along the character section, aplurality of ratchet teeth equally spaced along the ratchet section, andsecond means enacting with said ratchet section for stopping said wheelssubsequent to their release by said first means including, a pawlaligned with each ratchet section and adapted to engage one of the teeththereon and stop each printing wheel from rotating with the shaft in onedirection but permitting the wheels to rotate with the shaft in theother direction at all times, settable control means defining selectedcharacter positions of each wheel, an electrically operated actuator foreach pawl for driving same into and out of engagement with itsrespective ratchet section, and switch means associated with eachactuator and driven by said shaft in synchronism with said printingwheels for selectively energizing each actuator to move each pawl intoengagement with a tooth on a ratchet section and stop each printingwheel at a preselected position as determined by said sctt able controlmeans for printing a series of preselected characters, said switch meansincluding a single contact plate having a plurality of spaced contactsadapted to be connected to said actuators and a single wiper armconnected to said shaft and engageable with said contacts, said wiperarm being synchronized at home position with said wheels by said firstmeans.

5. A printing device as defined by claim 4, and means coating with saidwheels for detecting the non-operation of each actuator during theprinting phase.

6. A printing device for printing a selected character during theprinting phase comprising, a rotatable shaft, a printing wheel mountedfor rotation on said shaft, means for frictionally coupling saidprinting wheel to said shaft including a plurality of friction shoesguidably held by said wheel and spring means for urging said shoes infrictional engagement against said shaft, means for stopping said wheelto preset same at a home position and thereafter releasing same, saidprinting wheel having a character section and a ratchet section, aplural ity of characters and a symbol equally spaced along the charactersection, said symbol being in print position when the wheel is preset bysaid stopping means at the home position, a plurality of teeth equallyspaced along the ratchet section, one corresponding to each character,and means coacting with said ratchet section for stopping said wheel ata preselected position including, a pawl aligned with said ratchetsection and adapted to engage one of the teeth thereon and stop saidprinting wheel from rotating with the shaft, an electrically operatedactuator for said pawl to drive same into and out of engagement with theratchet section, settable control means defining selected characterpositions of said Wheel, and switch means associated with said actuatorand driven by said shaft in synchronism with said printing wheel forselectively energizing said actuator to move said pawl into engagementwith a tooth on the ratchet section and stop said printing wheel at apreselected position as determined by said settable control means forprinting a preselected character, and said switch means including asingle wiper arm driven by said shaft in synchronism with said wheel,spaced contacts engageable with said wiper arm when operated by saidshaft, and means coacting with said wheel for detecting thenonfunctioning of said actuator by driving said printing wheel to homeposition so that the symbol is in print position during the printingphase.

7. A printing device for printing numerical values during the printingphase comprising, a shaft means for oscillating said shaft through apartial revolution, a plurality of printing wheels mounted on said shaftand frictionally coupled thereto to normally oscillate therewith, a stopbar adjacent said wheels and parallel to said shaft, means on saidwheels coacting with said stop bar for stopping said wheels in a homeposition to preset same and in a second position, each printing wheelhaving a character section and a. ratchet section, a plurality ofcharacters and a symbol equally spaced along said character section,said symbol being in print position when each wheel is stopped by saidstop bar in said second position, a plurlity of teeth equally spacedalong the ratchet section of each wheel, one corresponding to eachcharacter, and means coacting with the ratchet section of each wheel forstopping said wheel at a preselected position including, a pawl alignedwith each ratchet section and adapted to engage one of the teeth thereonand stop the corresponding printing wheel from rotating with the shaft,an electrically operated actuator for each pawl to drive same into andout of engagement with the ratchet section, settable control meansdefining selected character positions of each wheel, and switch meansassociated with said actuators and driven by said shaft in synchronismwith said printing wheels for selectively energizing said actuators tomove said pawls into engagement with a tooth on the ratchet section ofeach wheel and stop each printing Wheel at a preselected position asdetermined by said settable control means for printing a preselectedcharacter, said switch means including a single Wiper arm driven by saidshaft in synchronism with said wheels, and spaced contacts engageablewith said wiper arm when operated by said shaft, and means coacting withsaid wheels for detecting the non-functioning of an actuator by drivingsaid printing wheel to said second position during the printing phase sothat the symbol is in print position.

8. A device for positioning a series of selected characters along a linecomprising, a rotatable shaft, means for continuously rotating saidshaft in one direction, a plurality of wheels mounted on said shaft andfrictionally coupled thereto to normally rotate therewith, first meansfor stopping said wheels to preset same at a home position andthereafter releasing same, each wheel having a character section and aratchet section, a plurality of characters equally spaced along thecharacter section, a plurality of ratchet teeth equally spaced along theratchet section, and second means coacting with said ratchet section forstopping said wheels subsequent to their release by said first meansincluding, a pawl aligned with each ratchet section and adapted toengage one of the teeth thereon and stop each wheel from rotating withthe shaft, an electrically operated actuator for each pawl for drivingsame into and out of engagement with its respective ratchet section,settabie control means defining selected character positions of eachwheel, and switch means associated with each actuator and operated bysaid shaft in synchronism with said wheels for selectively energizingeach actuator to move each pawl into engagement with a tooth on aratchet section and stop each wheel at a preselected position asdetermined by said settable control means for positioning a series ofpreselectcd characters, said switch means including a single wiper armfrictionally coupled on said shaft and synchronized at home positionwith said wheels by said first means, and spaced contacts engageablewith said wiper arm when operated by said shaft.

References Cited by the Examiner The following references, cited by theExaminer, are of record in the patented file of this patent or theoriginal patent.

UNITED STATES PATENTS 2,133,865 10/1938 La Boiteaux l0l93 2,742,8554/1956 Hofgaard 10l93 2,796,830 6/1957 Hilton 10l-93 ROBERT E. PULFREY,Primary Examiner.

WILLIAM F. MCCARTHY, Assistant Examiner.

